Method and means for flexible tubing fabrication and product thereof



March 23, 1965 K D BRO N 3,174,512

. W METHOD AND MEANS FOR vFLLIXIBLE TUBING FABRICATION AND PRODUCT THEREOF Filed Aug. 5, 1959 2 Sheets-Sheet 1 INVENTOR. KENARD D. B ROWN ATToRN March 23, 1965 K. D. BROWN 3,174,512

METHOD AND MEANS FOR FLEXIBLE TUBING FABRICATION AND PRODUCT THEREOF Filed Aug. 3, 1959 2 Sheets-Sheet 2 R INVENTOR.

KENARD D. BROWN ATTORNEY United States Patent O 3,174,512 METHOD AND MEANS FR FLEXHBLE TUBMG FABRICATON AND PRODUCT THEREGF Eenard D. Brown, Fort Coilins, Colo. (1227 S. Willow St., Casper, Wyo.) Filed Aug. 3, 1959, Ser. No. 831,260 Claims. (Cl. 13S- 133) The present invention relates to an improved type of flexible tubing or similar structure and to related irnprovements in a pump sucker rod and to the method and means for providing such improved structures.

, The present application is a continuation in part of my copending application, Serial No. 792,143, filed the 9th day of February, 1959. As set forth in the copending application, it has been found advantageous to provide a tubing structure which is of flexible nature though capable of withstanding high operating pressures. A general summary of the advantages to be expected from the use of such tubing when made up of a plastic liner and multi strands of steel wire for the reinforcing thereof would include the fact that the tubing may be made in long lengths without numerous joints. This feature alone enhances the operational characteristics of the apparatus, inasmuch as the absence of a great number of joints makes handling of the tubing more convenient and likewise tends to cut down internal flow friction. When such feaure is coupled with the use of a smooth plastic liner, it is expected that materials may be delivered through the tubing in higher volume than would otherwise be possible through joint lengths of steel pipe.

The improved interior surface condition and the absence of flow disrupting joints and the exposed metal thereof will make use of the present type of tubing especially advantageous in oil production where high paraffin oils having a relatively low solidification temperature are to be handled.

The foregoing features, together with additional advantages, are pointed out in my copending application. The specific advantages of the present embodiment of the invention are intended to satisfy the following further objectives.

The present invention is to provide structural features for tubing and well pump or sucker rod which make it easier and more economical to assemble a structure satisfying the objectives summarized above.

It is a further object of this invention to provide a structure which is adaptable to many varied uses inclusive of that of Well tubing, on-surface well delivery tubing, as turbine drill string for direct bore and offset drilling, and for other similar uses in which a flexible tubing having high flow delivery and high pressure characteristics is desired.

It is a further object of this invention to provide auxiliary structures of similar design and construction useful in connection with such tubing. Such structural modifications being inclusive of a well pump or sucker rod structure and a flexible insert cell adapted for passage through the tubing as necessary for selected purposes.

It is a further object of this invention to provide method and means for obtaining the structures desired.

Further objects and advantages of the present invention will be apparent from the appended description and drawings, in which FIG. 1 is an elevation in partial section showing the general structural features of an embodiment of this invention,

FIG. 2 is a cross-section view of the structure shown in FlG. 1,

FIG. 3 illustrates one method of use of the invention,

FIG. 4 shows an alternate method of use emphasizing the flexible features of the tubing structure, and

of other material.

FlG. 5 is an elevation in partial sectionY showing the structure of an insert cellular unit.

Briefly stated, the present invention provides alternate means for obtaining desirable structural characteristics in exible tubing and related units. A main distinction between the present application and that of my copending application is the use of independent reinforcing and tensioning wires which have been separately coated with a layer of protective material prior to assembly into the composite derived structure. The independent and separate protective coating of elastic or the like about each of the wires makes it easier to provide an assembled structure that is more flexible; that withstands high pressures; and, that is able to withstand the high tensional forces coincident with the use of a long string of tubing within a vertically disposed well structure.

4 In laddition to the adaptation of the separately coated wires to tubing, the present invention lshows the use thereof in the building of an insert cellular unit which is useful when introduced through a tubing liner to obtain a well plug or as a carrier unit for chemicals or explosives as necessary for wells or well structure development.

' Referring now to the drawings, the deailed features of a preferred embodiment of this invention is shown in FIGS. 1 and 2. Here a tubing structure which may be used for various flow delivery installations is shown. This tubing structure 11 includes an interior liner 12 which is preferably made of a resin base or plastic material of a type that will provide an extra smooth interior surface 13. Further, the liner 12 should provide a wall 14 of uniform thickness adaptable to flexural use.

While natural and synthetic rubbers could be used for such liner, plastic materials are preferred. It has been found that extruded nylon tubing satisfies most requirements of oil production and further provides a highly glazed internal surface 13. Other plastics are suitable and undoubtedly could be used to advantage for installations where different types of chemicals are to be carried by the tubing structure 11. It is recognized that other plastics, such as Teflon, may be used where improved characteristics for specific purposes are desired. If the tubing is to be used for the iiow delivery of oils having a low paraffin soliditication temperature, the smooth interior surface 13 or a material having a decreased chemical and mechanical ainity for parain is highly desirable. Since most of the materials that might be used to provide the flexible liner 12 have a relatively low tensile strength, and since cost factors dictate the use of relatively thin wall sections 14 for the liner 12, it is desirable to provide reinforcement to improve the burst strength of the structure. As in my copending application, this increased pressure resisting strength is obtained through use of a continuous, tightly wound, helical reinforcing wire 16 intimately disposed about the exterior surface 17 of the liner 12. Preferably the reinforcing wire 16 is made of a material having high tensile strength, such as steel. Where steel or other corrosible material is used, it is desirable to provide a protective coating 18, about the wire 16. As shown, this protective coating 18 may have a relatively thin wall section and may be made of the same type of plastic as the liner 12, as shown, or

Where plastics are used, the protective coating 18 may besextruded about the reinforcing wire 16 as it is passed through an extrusion die to obtain an intimate bond on the wire and a uniform Wall thickness. ln order to obtain the desired intimate bond between the wire 16 and protective coating 1S, it is desirable that the wire be acid etched prior'to its passage through the extrusion die. When the process is properly regulated, an intimate bond between the wire and protective covering 13 is obtained which is highly resistant 3 to destruction or displacement by abrasive and other forces.

In addition to providing anti-corrosion protection, the protective coating 18 prevents galling of the exterior face 17 of the liner 12 and of the longitudinal tension wires 19. Where these longitudinal tension wires 19 are likewise provided with a protective coating 21, as shown, the operational service life of the tubing will be greatly increased, and deterioration of the tubing or of the Wires 16 or 19 will he greatly minimized.

While the closely wound reinforcing Wires 16 are used to provide a high pressure structure, it is recognized that in certain usages the tubing structure 11 will have to further provide resistance to high tensile stresses. The longitudinal tension wires 19 are provided for this purpose. These wires are disposed about the tubing structure 11 in longitudinal arrangement. As shown, these wires may be disposed in side-by-side arrangement or may be spaced each from each about the external surface of the reinforcing wires 16. In order to maintain optimum flexural characteristics and further to prevent any tendency of the tensional forces in the wires 19 to collapse the tubing structure 11, spiral placement of the tension wires 19 should be avoided. However, it is recognized that these wires may satisfactorily serve their purpose even though disposed in loose spiral arrangement. Accordingly, any terminology inclusive of the Word longitudinal used in description of the tension wires 19 is intended to include any arrangement of Wires in which the pitch distance for any developed spiral is greater than ten times the diameter of the derived spiral.

With this preferred arrangement of the longitudinal tension wires 19, any tendency of such wires to restrict the flexural bending of the combined structure 11 is eliminated. However, it is recognized that the longitudinal wires 19 should be confined in some manner so that they will not be caught on obstructions Within the well casing or on similar objects during surface usage.

While an exterior continuous plastic sheeting may be used, as shown in my copending application, it has been found that a further shield wire 23 may be used in spiral or coiled arrangement about the exterior surface of the longitudinal tension wires 19 to hold the Wires in a closely knit bundle. This wrapping layer made of the shield wire 23 may likewise be provided with corrosion and abrasion protection through provision of a coating 24 on the surface thereof. As illustrated, the pitch distance for this helically wound shield wire 23 is less than ten diameters and is preferably of approximately one helix diameter.

The tubing structure 11 described has many and varied usages. As shown in FIG. 3, the tubing may he readily transported on vehicles to positions of use. In the servicing of well structures the tubing may be introduced and removed from the Well 26 by actuation of a power driven reel 27 mounted on a truck vehicle 28. The tubing may be passed over a sheave 29 of relatively small diameter disposed on a boom 31 for straight line introduction into the well. For usage in which fluid is to be pumped through the tubing 11, a fiow delivery system 32 may be connected directly to the central trunion 33 of the reel 27 for passage through the end of the tubing hooked to the reel.

At any time that the tubing is to be removed for use at another site or for cleaning, the entire length of the tubing 11 may be retrieved and coiled upon the reel 27. Since the tubing may be made in long lengths, all interruptions for the purposes of joining the tubing are avoided. These quick placement and removal features of the invention likewise make this type of tubing highly useful for on-surface use.

As shown by the dotted line representation in FIG. 3, the tubing 11 may be laid out or picked up from surface locations readily and easily through use of the reel structure 27. It is contemplated that the invention will be snr/4,51

of great utility in well servicing operations. With the high mobility and quick installation and removal features, it is expected that in some instances several wells may be serviced by a single servicing unit. With a lowered proportionate capital expenditure, the profit margin may be improved.

On other installations where paraffin coagulation of conventional tubing is expected, the provision of the highly polished interior surface 13 having a decreased affinity for deposited parafiins will be a boon to oil producers. A system which cuts down or eliminates parafn deposits and which may further be readily removed from the well structure for cleaning if necessary presents a twofold improvement over present conventional practices.

The flexible and pressure resistant characteristics of the tubing structure 11 suggest further uses for such tubing. As shown in FIG. 4, the tubing may be reeved over idlers 34 and bull wheels 36 of small diameter for introduction into a well structure. At the same time application of fluids under high pressures makes it possible to use the tubing 11 as a flow delivery system for a turbine drill 37. When used with a turbine drill, the flexible characteristic will make it possible to more economically accomplish offset drilling in which the tubing 11 will be passed through a window 38 in the Well casing 39 to drill lateral or angular openings 41 through oil bearing or other strata.

The smooth interior face `13 of the liner 12 makes it possible to insert various kinds of well servicing apparatus. In FIG. 5 an insert 43 is shown which may be introduced through the tubing i1i1 to pass through and around any bends therein. iIn the embodiment shown, the insert 43 is used to enclose a granular material 44 within the liner 12. In this modification of the flexible structure, which is for use with explosive materials, the closely wound helix wires 16 surround the liner 12 but are themselves enclosed within a jacket `46, lthe ends of which 'are closed off by the cap member 47. The jacket 46 is provided so that the pressure influences at the bottom `of a well will not be able to compact the explosive `granular material 44 within the l-iner y12. iIt has been found that the wires 16 are effective in resisting external pressures as well as internal pressures when covered with a pressure distributing layer such as the jacket 46. If the insert 43 is used in conjunction with the directional drilling features possible with use of the turbine drill 37, it would be kpractical to drill many openings out into ya formation and to successively pull back and plant a plurality of explosive inserts 43 in spaced positions in such -openings as necessary to completely fracture an oil bearing structure.

In all of the embodiments of the invention shown and described, it should lbe noted that each element of the `combined structure is a separate piece in itself which, though joined with other elements for cooperative action, still has individual freedom. With this 'arrangement each element is free to act independently of the other elements under the influence of forces directed against such element. This freedom `of independent action has been found to be highly beneficial, inasmuch as displacement or tearing of one element due to forces acting on and moving another element is minimized.

While each element has the freedom of independent action, the bundled type cooperative structure obtained is able to utilize and develop the lfull strength of each of the separate elements. In the unity there is strength to withstand the stresses of usage; and the resultant strain is absorbed by movement 'and deformation of the individual elements of the structure without the necessity of corresponding deformation of the other elements of the structure.

While uses of the present structure have been described in the eld of oil production and fluid flow, it should be realized that the tubing structure has many other additional and potential uses. A structure similar to that `shown in FIG. 5 for the explosive insert 43 has been utilized for a carrier of granular or powdered metals. Further, -tests have been made on a structure in which the granular material illustrated is a highly compacted powdered metal and in which the end cap members 47 are of electricity `conducting type material. This modified structure may be used in long lengths as an electrical conductor Isuitable for above-ground or below-ground usage.

While separate embodiments of the invention and methods have been shown and described, it is apparent that the present invention is adaptable to various modifications and changes. -All such modifications 'as `come within the scope of the hereunto appended claims are deemed to be a part of this invention.

What is claimed is:

`l. A tubing structure comprising a liner of moldable ma-terial, a helical reinforcing element comprising a multiplicity of coils disposed in gripping engagement about the exterior surface of said liner, a protective plastic coating on said reinforcing element for direct engagement with the exterior surface of said liner to reduce frictional wear between said liner and said reinforcing element, said element and said liner being capable of at least limited movement with respect to one another substantially throughout the length of said element, and a plurality of separate longitudinal tension members disposed along said structure in engagement with the outer peripheries of the coils of said reinforcing element.

2. A tubing structure comprising a liner yof moldable material, a helical reinforcing element comprising a multiplicity of coils disposed in gripping engagement about the exterior surface of said liner, a protective plastic `coating on said reinforcing element `for direct engagement with the exterior surface 'of said liner to reduce frictional Wear between said liner and said reinforcing element, said element and said liner being capable of at least limited movement with respect to one another substantially throughout the length of said element, a plurality of separate longitudinal tension members disposed along said structure in engagement with the outer peripheries of the Icoils -of said reinforcing element, and a `shield member disposed about the exterior of said longitudinal tension members Ifor holding all of the named elements in bundle arrangement.

3. A tubing structure comprising ya plastic lliner having a thin wall section of relatively limited internal pressure resist-ing capacity, a reinforcing element disposed about the exterior surface `of said liner in gripping engagement therewith, said reinforcing element being made up of a plurality of convolutions of a high tensile strength material having a protective coating thereon and with each of said convolutions in substantial-ly continuous engagement with the next, said protective lcoating `on said reinforcing element being in direct impinging engagement with the exterior surface of said liner and with adjacent `convolutions and affording at least limited relative movement substantially throughout the length of said element and to reduce -frictional wear between said reinforcing element and said liner and between said convolutions, said structure providing a tubing of increased internal pressure resisting -characteristics resulting from the interaction between said liner and said reinforcing element and between adjacent ones of said convolutions, and a plurality of longitudinal tension members disposed along the outer surface of said reinforcing elements.

4. A tubing structure comprising a plastic liner having a thin w-all section of relatively limited internal pressure resisting capacity, a reinforcing element disposed about the exterior surface of said liner in gripping engagement therewith, said reinforcing element being made up of a plurality of convolutions of a high tensile strength material having a protective coating thereon Iand with each convolution in continuous engagement with the next, said protective coating Aon said reinforcing element being in direct impinging engagement with the exterior surface -of said liner and with adjacent `convolutions of said element to reduce frictional wear between said reinforcing element and said liner 'and between adjacent convolutions and affording at least llimited relative movement substantially throughout the length 'of said element, said structure providing a tubing of increased internal pressure resisting characteristics resulting Vfrom the interaction of said liner and said reinforcing element, a plurality of longitudinal tension members disposed Ialong the outer surface of said reinforcing elements, and a shield member disposed about said longitudinal tension members for holding all of the named elements in bundle arrangement.

5. -A tubing structure comprising a liner of moldable material, a helical reinforcing element disposed tightly about the exterior surface of said liner in gripping engagement therewith, said element comprising a wire and a protective coating of moldable material completely surrounding said Wire and in direct engagement with the exterior surface of said liner, a plurality -of separate longitudinal tension members disposed along said structure in engagement with the `outer edges of said element, each of said tension members comprising a Wire and a protective coating of moldable material completely surrounding the wire, said element Iand said liner and said tension members being independent of one another and affording at least limited relative movement therebetween substantially throughout their lengths, and means disposed about the exterior of said longitudinal tension members for holding said members closely in engagement with said reinforcing element.

References Cited by the Examiner UNITED STATES PATENTS 881,584 3/08 Hoffman 13S-144 X I1,136,329 4/ 15 Goodall 1138-134 1,465,801 8/'23 `Bell 57-144 1,697,541 11/'29 Shurer 57-144 X 1,896,285 2/ 33 Burd 138-1'34 X 1,900,5111 13/33 Madden 138-13'1 X `1,910,642 -5/33 Sherrard 138-1-45 1,969,540 `8/'34 Bergstrom et al '138-145 X 2,035,088 E i/36 McNamee 13S-138 X 2,181,475 lll/'39 Bourdon 57-149 X 12,448,485 `8/48 Chernack 138-133 `2,577,049 l12/51 Uline 1138-138 X 2,657,866 1'1/5-3 Lungstrom 242-11 i2,725,7"13 `12/55 Blanchard 1138-134 X i2,782,861 `1/56 Gilmore 138-134 X 2,739,616 3/56 Duif 13S-12,2 l2,766,806 10/56 Rathermel et a1. 138-138 y2,783,819 3/57 Du 154-8 12,822,989 Q/SS Hubbard et al 242-11 `2,894,536 7/59 Arnot 13S-134 X '2,898,942 `8/ 59 Rathermel 138-122 V, BENI-IAM, Primary Examiner. 

1. A TUBING STRUCTURE COMPRISING A LINER OF MOLDABLE MATERIAL, A HELICAL REINFORCING ELEMENT COMPRISING A MULTIPLICITY OF COILS DISPOSED IN GRIPPING ENGAGEMENT ABOUT THE EXTERIOR SURFACE OF SAID LINER, A PROTECTIVE PLASTIC COATING ON SAID REINFORCING ELEMENT FOR DIRECT ENGAGEMENT WITH THE EXTERIOR SURFACE OF SAID LINER TO REDUCE FRICTIONAL WEAR BETWEEN SAID LINER AND SAID REINFORCING ELEMENT, SAID ELEMENT AND SAID LINER BEING CAPABLE OF AT LEAST LIMITED MOVEMENT WITH RESPECT TO ONE ANOTHER SUBSTANTIALLY THROUGHOUT 